Year	% of land area
1961	5.457156005013563
1962	5.519963738725355
1963	5.564046614531872
1964	5.625265153661297
1965	5.66990079280081
1966	5.659951052806863
1967	5.679574151128259
1968	5.740309022341312
1969	5.800422034804743
1970	5.748738663169517
1971	5.793305206892406
1972	5.8384936093649165
1973	5.8344860752006875
1974	5.80099693622455
1975	5.801019075535139
1976	5.848835746969653
1977	5.86106631177299
1978	5.898587197017124
1979	5.927263380030597
1980	5.942119715808661
1981	5.926365089960296
1982	5.94730215852194
1983	5.962365792008535
1984	5.9582198378379125
1985	5.967962830138876
1986	5.978880509454848
1987	5.953106494360811
1988	5.96996670798801
1989	5.9742508606309865
1990	6.0916504628957835
1991	6.17560603485089
1992	6.236344263450512
1993	6.426919956826797
1994	6.433968078916855
1995	6.615215375409241
1996	6.743394458517655
1997	6.796669969610156
1998	6.824586061025681
1999	6.826866335819524
2000	6.8441411448637846
2001	6.915211091256597
2002	7.0137852976173205
2003	7.342489332665365
2004	7.353245627045744
2005	7.538190372702064
2006	7.620983333741133
2007	7.774221297242286
2008	7.826326733632518
2009	8.027872158319822
2010	8.225426502263678
2011	8.404555644002283
2012	8.67718500713952
2013	8.827011659665517
2014	8.902444428431966
2015	8.95840488847539
2016	9.072160411394712
2017	9.17761700521171
2018	9.253022545432371
2019	9.286505428952223
2020	9.316110048087564
2021	9.353457536561475